Symptoms last an average of 57 days, if untreated. So far no infected Floridians have been hospitalized. However, at least 18 in other states have been.

The CDC could not yet determine whether all the cases were part of the same outbreak.

Those infected usually ingest water or uncooked food contaminated with human feces. Cyclospora is not passed from person to person.

"Epidemiologists across Florida, in coordination with the CDC, are working to identify the source of these cyclospora cases," said Dr. Carina Blackmore, an epidemiologist with the state's health department.

"Staff are interviewing those affected to carefully examine food items and the ingredients those patients were exposed to," Blackmore said.

Onset dates of cyclospora cases in Florida range from the beginning of June to mid-July. The health department could not provide a county-by-county breakdown.

However, no common food items or events, such as a social gathering, have been identified among those affected.

"Our last outbreak of cyclospora was in 2005 and was linked to basil," said Ashley Carr, health department spokeswoman.

Across the country, the hardest hit state has been Iowa, which reported the outbreak's first two cases in early June. As of Tuesday, Iowa had reported 140 cases. Texas had reported 71 cases and Nebraska 70.

Other states reporting at least one case include Arkansas, Connecticut, Georgia, Illinois, Kansas, Minnesota, Missouri, New Jersey, New York, Ohio and Wisconsin.